Earth auger



F. E. HENNING April 25,- 1950 EARTH AUGER Filed Feb. 11, 1946 INVENTOR.

AT T 012M575 Patented Apr. 25, 1950 UNITED STATES BATENT OFFICE 2,504,978 EARTH AUGER Frederick E. HenninggFargo, N. Dak. Application February 11, 1946, Serial No. 646,871

"quickly drilling through hard earth and even rocky soil to cut and at least, partially, remove upwardly, the earth to form a socket for receiving a post, footing or analogous member.

A further object is the provision of a highly emcient rotary earth drilling tool wherein the downward thrust force and cutting torque are most efficiently applied and distributed to a multiplicity of upwardly staggered, successively operating cutting edges provided by two or more blade assemblies whereby accurate alignment is obtained in the rotary drilling with the attainment of a very high cutting efliciency relative to the downward force and torque applied.

More specifically, it is an object to provide an earth auger of the class described having a revoluble cutting head provided with at least a pair of circumferentially spaced blade assemblies extending outwardly from the actual portion of the edges starting from the axis ofthe head and substantially corresponding in number in the two or more assemblies and having the successive cutting edges of the head in their engagement with the earth, progressively elevated from the axis of the head outwardly.

Still another object is the provision of highly efficient cutting blades with a centering element and material removal means to cause a general upward movement'of the material from the time itis first out and to also facilitate precise alignment of the tool in drilling a'hole.

- Another object is the provision of an earth auger of high efiiciency wherein the cutting and drilling elements may be readily removed and attached for replacement or sharpening,

acters refer to the same parts throughout the several views and in which-- Fig. 1 is a side elevation of an embodiment of my invention;

Fig. 2 is a similar side elevation with the head rotated toapproximately:90;

' 6 Claims. (Cl. 255'-69) 2 Fig. 3 is abottom plan view of the device; and Fig. 4 is a' top plan view of the head with the spiral material-removing element broken away, and Fig. 5 is a side'elevation showing a somewhat different form of blade assembly and attachment seat formed in the associated wing.

In the form illustrated in the drawing, I provide a heavy cutting head designated as an entirety by the letter H having an axial hub 6 provided in its upper portion with a longitudinal, squared socket to receive the squared lower end of a torque-applying shaft 1 and as shown, tapering downwardly toward its lower end which is provided with an axially disposed squared socket 'for receiving a hard metal screwdrill 8.

The head H includes a pair or more of circumferentially spaced, outwardly extending blade attachment wings 9 and I0 which may be integrally cast or otherwise 'very rigidly and strongly connected with the hub 6, said wings having flat leading faces 9a and Ilia respectively (with reference to turning action) which are disposed almost radially of the hub 6 but which are declined slightly from the vertical, as clearly shown in Fig. 2. "The leading faces are rabbeted or recessed plana'rly-and along serrated or' stepped, transverse lines 9b and [0b respectively, to form for each wing, a'shouldered seat for receiving blade, assemblies' II and I 2 respectively which as shown in the drawings, comprise for each wing an integral, multi-edge blade It will be noted that the blade shoulders defined by the transverse, stepped lines 91) and lOb respectively, are inwardly beveled or converge with respect to the planar recessed blade- -receiving cheeks, thereby serving to retain the complementary shaped shoulder engaging edges of the blade assemblies II and I2.

It will be noted by inspection of Fig. 1 that the two blade assemblies H and l2 have inverted, .stepped' cutting edges extending generally outwardly and successively elevated from the axial portion of the diminished lower portion of hub 6.1 It will further be noted that successively in turning or. ground cutting relation, the successive edges of the two blade assemblies II and 12 are progressively spaced outwardly and radially as clearly shown in Fig. 1. Thus, referringto the relationship of the twoblade assembliesfit will be noted that assembly H is provided with first, a relatively narrow, depending cutting edge Ila disposed closest of all cutting edges to the axis of the head and blade I2 is provided with an inner, horizontal cutting edge lZa disposed at a somewhat higher elevation than the first mentioned edge Hoe of the assembly ll. Edge l2a,

3 it will be noted, extends radially outward some distance beyond the cutting width of edge Ila. The next successive cutting edge I lb provided by blade assembly I l is disposed at a slightly higher elevation than the cutting edge 12a and overlaps in turning action, the radial working stroke of the blade |2a and extends in its cutting action for some distance outward thereof, radially. The next cutting edge I2b of blade assembly [2 extends at a slightly higher elevation than the edge lib; overlaps in its rotary cutting operation the circumferential path of the blade llb. Similarly related in accordance with the progressively elevated and progressively radially extending: positioning, I provide the cutting edges Hc, I20, lld, l2d and He 01": the two blade assemblies. said cutting edges are preferably defined by beveled surfaces intersecting the leading faces of the blade assemblies. Blade assemblies II and [2 may be retained against the cheeks and shoulde rs of the blade seats onwingsll and I0 respecti'vely, by a suitable means such astwoor more transverse bolts 53, the heads-of which are prefer- ..ably' counter-sunk in the leading faces of 1 the blades and which extend through suitable aper- "tures formed in the blade assemblieswhich when the blades are properly seated, register with extension attachment aperture formed transverse- 1y through the wings 9 and ID of the head.

' A spiral conveyor section I4 of similar external.diameter to the maximumdiameter of head H (including the full length of the wings :9. and

Ill), is rigidly affixed to and sur-roundsthe upper portion of hub member 6 and preferably includes approximately one screw convolution receiving from the flat leading face of the blade H and its blade-receiving wing 9.

In operation, my auger is-vertically-positioned in.the desired location to dig a holeand'rotary power is applied by power take-off or hand to ,the upper end of the shaft 1. -Th screw drillgfl iyst penetrates the top-0f the ground'centering the-device and determining-the axis of the, drill- -ing operation. Thereafter, cutting edgeslla,; l-Za,

I Ib, I219, llc I20, lid, IZd and lie-successively engage in their rotative movement in thesoil, each successive edge being progressively. elevated and cutting a circumference extendingradially outwardly of the circumference of the preceding cntting edge mounted on the adjacent or other wing. Thus, it willbe seen that with the progressively elevated and outwardly extended cut- ,tin edges starting from the axisof the head,

the downward thrust of the cutting jfOlCE is very uniformly distributed thereby assuring the .desired alignment and guiding of the tool, during the drilling operation and furthermore, distributing both thrust and torque force to render a highly efficient cutting action,

Because of the cooperative relationship of the upwardly inclined leading planar faces of the blades Ii and [2, the material cut by all of the said cooperating edges is forced upwardly as it is cut, thereby at the top of the wings 9 and I0,

,being received by the revolving spiral conveyor beveled to correspond. with the beveled surfaces;

The

; torque ina very efficientmanner. It will further beseen that thecutting of the material is progressively applied from the axis outwardly through the successive action of the progressively elevated series of edges on the two or more blade assemblies.

It will of course, be understood that various changes maybe made in the form, details, ar-

rangement and proportions of the parts without departing from the scope of my invention.

In Fig. 5, a somewhat different form of blade seat and a reversiblebladeis shown. Here-the blade-2| has the progressively outwardly-and upwardly disposedcutting edges -2Ia to. Zjie respectively and has its opposite. and Seating-edge provided with similarly and oppositelyv formed cutting and seating edges 2lf.to 2 l j inclusive. Both sets of edges are formed bybevels in the material, the opposite, faces ,of the blade being. beveled along. the two sets ofedges. Th supporting wing It is. provided with asteppedset complementarily shaped to the multiple cutting edgeof the blade and beveled in accordance therewith. vItwill be obvicusthatin this;forrn when the edges Zia to Zlebecome Worn, the blade may be inver ed and reversed fromthepositionshown to enable the edges; if. to. 2 ii to be substituted.

'What I claim is:

1. An earthauger having in combination a revolubleshaft and a cutting head attached to the lower endthereof, said headoomprising at least a pair of circumferentially spaced, radiall extending blade-attachment wings, said wings having leading, upwardly extending faces with respect to the direction of rotation of said head, at

least apairof bladeassrmblies, said faces being recessed and transversefy shoulde:ed to receive in each instance,'one.,of said blade assem" lies,

,said blade assemblies extending from ptints ad- ,jacent the axis of saidhead outwardly tothe outerzends of .said wings and presentingin combination with referenc to turningrnovement of said head, a multiplicity ofsuccessivel elev ted and successively, outwardly extending cutting edges.

2. The structure set forth iii claim l. and said wing faces being transverselyshouldered for receptionofthe upper edges of-saidblad assemb lies, said shoulders being beveledinwardly to retain the abutted attachment edges ofsaid blades.

3. ,An earth auger having in Combination a rotary head comprisin atflleast pair-of circumferentially spaced radially :extending blade attachment wings, said wings having leading, up-

wardly extending faces wifhlxespect toithedirection of rotation of said head, at least a pair of blade assemblies, said faces being recessed and transverseiy shouldered along an inverted, stepped line to receive in each instance, oneof said blade assemblies, said blade assembliesextending from .points adjacent-the axis of said head outwardly to the outer ends of said win s and each present ing-a mul iplicity of successively elevated cutting edges defined by an inverted stepped line, said .bladeassernblies each having an opposite end defined by an inverted-,steppedline-of an opposite configuration to the line defined by said first mentioned cutting edges whereby said blade may be inverted and reversed to selectively utilize either of said edges for cutting.

4. The structure set forth in claim 3, the two sets of cutting edges being defined by beveled surfaces on opposite faces of said blade assemblies and the shouldered edges of said faces being inwardly beveled to anchor the received edges of said blade assemblies.

5. An earth auger having in combination a revoluble head with axial coupling connection for non-rotatively receiving th lower end of a revoluble shaft, said head having rigidly secured thereto at least two series of cutter blades extending generally radially of said head, the blades of each series having horizontal cutting edges vertically spaced and disposed successively at higher elevations and the blades of each series having substantially vertical cutting edges successively extending outwardly from bottom to top of said head greater distances from the axis of said head, the horizontal cutting edges of th successive and corresponding blades of said two series being succesively elevated from bottom to top and the vertical cutting edges of said two series being alternately and successively disposed greater distances from the rotational axis of said head, and all of said blades having leading upwardly inclined faces with respect to the direction of revolution of said head to successively elevate material cut.

6. The structure set forth in claim 5 wherein said blades are all provided with beveled undersurfaces and wherein the successive leading faces of the blades of each series are offset slightly rearwardly relative to the direction of revolution.

FREDERICK E. HENNING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 829,633 Decker Aug. 28, 1906 1,486,898 Hundrieser Mar. 18, 1924 1,961,390 Ragsdale June 5, 1934 2,014,909 Pearce Sept. 17, 1935 2,149,798 Starkey Mar. 7, 1939 2,401,250 Kandle May 28, 1946 FOREIGN PATENTS Number Country Date 519,475 Great Britain Mar. 28, 1940 

